The present invention relates to a planetary geartrain used in automotive automatic transmissions.
A previously used planetary geartrain uses a multiplate brake assembly which connects a A member of the planetary geartrain to a reaction member in the forward first and reverse gear positions, and also uses a multiple clutch assembly which connects the A member to a input shaft in the direct drive and overdrive gear positions.
Because of the large capacity of the multiplate brake assembly which connects the A member to the reaction member, the previous type of automatic transmission has a drawback to create large amount of drag resistance when the multiplate brake assembly is released in the direct drive and overdrive gear positions and aggravates a fuel economy of automobile.